Installing Welding Gun; Connecting A Spoolmatic 30A Gun; Setting Gun Polarity For Wire Type - Miller Millermatic 300 Owner's Manual

3-5. Installing Welding Gun

3-6. Connecting A Spoolmatic
The Spoolmatic 30A welding gun connects directly to the 10-pin receptacle on the front of the welding power source −
no adapter required. NOTE: Two welding guns may be connected to the welding power source at the same time, but
only one welding gun may be in use at any one time. If the triggers of both welding guns are pulled at the same time, the
weld output and wirefeed motor are disabled.

3-7. Setting Gun Polarity For Wire Type

Wire Drive
Assembly Lead
+
Shown as shipped − Electrode Positive (DCEP): For
solid steel, stainless steel, aluminum, or flux core with
gas wires (GMAW).
Electrode Negative (DCEN): Reverse lead connections
at terminals from that shown above for gasless flux core
wires (FCAW). Drive assembly becomes negative.
R
30A Gun
Changing Polarity
Work Clamp Lead
D
-
Positive Terminal Negative Terminal
1
3
4
2
D
1 Drive Assembly
2 Gun Securing Knob
3 Gun End
Loosen securing knob. Insert gun
end through opening until it bottoms
against drive assembly (make sure
gun end does not touch drive rolls).
Tighten knob.
4 Gun Trigger Plug
Insert plug into receptacle, and
tighten threaded collar.
Close door.
Ref. 802 517-A
1 Polarity Changeover Label
Information
Always read and follow manufac-
ture's recommended polarity.
1
3/4, 11/16 in
Ref. 190 821-A
OM-1321 Page 11